Writing with solder

                                    So recently(the last few months) I have become obsessed with the idea of conductive inks and making circuits on fabric and paper, I think it is sheer brilliance to be able to design and build circuits as seamlessly as drawing on a piece of paper, now there are several products which achieve this , such as conductive thread , conductive ink and writing instruments etc (search for bare conductive on google).The thing is that by designing tools and technologies which enable us to do so will allow us to deal more with these circuits , we feel it as art, and because it is so much more simpler and fun we will do it more often not to mention the infinite creative possibilities which it will open up. Such a wonderful thought it is.

So being inspired and all I was looking at ways it can be done, here is what I tried.

•  First the simplest thing, you know pencil is made of graphite, and it is a good conductor of electricity, so I tried making marks of pencils on paper and measure the resistance. Obviously you need to make a very dark mark and greater the thickness greater is the conductivity. Typically with a mark of about 1cm long an 3 mm wide the resistance was about 400 k ohms and it was pretty much obeying ohms law( the longer the mark the greater the resistance)

•  Next it struck me that if I make two patches of pencil marks on the either side of the paper it will for a capacitor I tried it out but did get the chance to test it ( exams and all right now ), but it should have it in the order of picofarads .

•  Finally I decided to make an el cheapo version of a silver ink pen, to make it cheap, it does not have silver ink, instead as you write it leaves a solder wire on the paper( non melted), there are improvements to make like making the solder wire adhesive and making the tip a heating element do it can be fixed to any ic pin without any extra tools.
  
  
  
  So this is what i made till now i converted a normal pen to dispense solder wire, i made a spindle on the top with the refill and an aluminum pipe, it does not look pretty but it all i had at 4 am in the night, i will post an instructable on this soon
  
  
  
  This is how the solder path looks
  
  
  
  
  
  I know this is very trivial, but it is sort of nice, ill post more when i improve it
  Coming up resistor pen -set the value draw the resistor
  bye for now
  
  

Experiments with oobleck and homemade magnetorheological fluid

So i have tried to use the famous oobleck as a smart surface by making it harden under command by passing ultrasound waves through it, so what happened is well........NOTHING, turns out that you need a lot more acceleration to see any appreciable changes in its solidity.(tried out a small vibration motor as well, but as expected nothing happened).

Another failure is trying the same with a homemade magneto rheological fluid , but this time applying a magnetic field....still no appreciable results...but i think i will get a custom fluid form the metallurgy department and try more.Wish me luck.

The above picture is of the iron filings we collected from the construction site to make the magnetorheological fluids. we made acolloidal solution of this with vegetable oils.